Why does the program crash on clicking a column heading in a c# datagrid?

Question

C++ / C#

In general, there are several pairs of data grids, and when you click on any of the column headers where the user enters a value, the program crashes and shows an error not on the form where the data grid is located, but sends it to the .cs file from which the program starts, it would seem then here, but there is still a feature that when you click on the same column header, without entering data, everything is ok. I’ll also clarify that when you click on the column header, the datagrid sorts, and it doesn’t matter if there is a value there or not, it sorts them anyway, and they are null there by default, and this is strange, but when the user entered values ​​in 1 column in Their program considered him a friend, I can sort another column, and where the user entered values ​​I can’t, crashes and throws these screenshots on the .cs file being launched:

Answer 1

At you the form is shown before start of application I correctly understood from a screen of source codes? If yes, then it is better not to do this, too many crutches will have to be used.